Elevator control system



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ELEVATOR CONTROL SYSTEM Original Filed Jan. 9, 1937 16 Sheets-Sheet 16WITNESSES: INVENTOR 6Z4 HGrO/QMM///&fl75

MM W a Patented Aug. 8, 1939 UNITED STATES PATENT OFFICE ELEVATORCONTROL SYSTEM Harold W. Williams, Englewood, N. J., assignor toWestinghouse Electric Elevator Company, Chicago, 111., a corporation ofIllinois 7 Claims.

My invention relates, generally, to electrical control systems, and ithas particular relation to such systems as applied to a bank of elevatorcars.

This application is a division of my application Serial No. 119,795,filed January 9, 1937 and assigned to the Westinghouse Electric ElevatorCompany.

The object of my invention, generally stated, is to provide a combinedelevator control and signalling system which shall be simple andefficient in operation and which maybe readily and economicallymanufactured and installed.

One object of my invention is to provide a sys tem for operating a bankof elevators so that all floors of the building being served willreceive the same service.

Another object is to give a prospective passenger an indicationimmediately after the operation of the fioor button at his floor as towhich car of the bank will respond.

Another object is to so apportion th'e floor calls among the elevatorsso that each car will receive its share and thus maintain a. uniformoperating schedule among the cars.

A further object is to provide a mechanism for each car responsive tothe calls registered that will limit the total stops for that car tripto a predetermined number.

A further object is to provide a dispatching mechanism that will startthe cars in rotation from the terminals at equal intervals of time.

A still further object is to provide means for starting any car at ashorter than normal interval if it has accepted its quota of calls.

Another objectis to restart the normal timing intervals when the carleaves after a short interval at the time the car leaves so that thenext car in the sequence will follow at a normal interval.

Another object is to assign the floors to the various cars such thateach car will accept floor calls only from floors between the carsposition and. the position of the next car ahead in the sequence.

Another object is to assign the down floors between the top terminal andthe highest down car to the nearest up moving car in the event thatthere is no car at the top terminal.

Other objects of my invention will appear hereinafter.

My invention, accordingly, is disclosed in the embodiment hereof shownin the accompanying drawings, and comprises the features ofconstruction, combination of elements and arrangement of parts, whichwill be exemplified in the construction hereinafter set forth and thescope of the application of which will be indicated in the appendedclaims.

For a more complete understanding of the nature and scope of myinvention, reference may behad to the following detailed description,taken in connection with the accompanying drawings, in which:

Figure 1 shows one car and a portion of another of a bank of elevatorsthat may be used in my invention.

Fig. 2 shows a motor driven timing device that may be used to dispatchthe cars from certain dispatching floors in a sequence and at regularintervals.

Fig. 3 in conjunction with Fig. 3A illustrates diagrammatically themotor control circuits and switches that may be used for two cars in anembodiment of my invention.

Fig. 4 in conjunction with Fig. 4A shows floor buttons and responsivecircuits and relays for registering calls for service from the variousfloors of the bank of elevators.

Fig. 5 in conjunction with Fig. 5A illustrates selecting relays andassociated circuits that are used in conjunction with the circuits inFig. 5 to cause the calls to be registered on the proper car.

Fig. 6 in conjunction with Fig. 6A shows the circuits and relays used ingiving a responsive signal at the floors when the floor buttons areoperated and in limiting the number of calls that a given car mayaccept.

Figs. '7, 8, 7A and 8A show circuits and relays of a dispatchingmechanism that may be used in this embodiment of my invention.

Figs. 9 and 9A show additional circuits and relays useful inaccomplishing the objects of my invention.

Figs. 10 and 10A show an alternate method of operating the quota relay,and

Fig. 11 shows the relative sizes and location of conducting segments andcontacting brushes of the selector mechanism used with each car of mysystem. Segments are illustrated for five floors, the first and fifthfloors being terminal floors.

The Figs. 3A through 9A may be assembled alongside of diagrams Figs. 3through 9, respectively. By arranging the various figures, each setbelow the preceding set starting with Figs. 3 and 3A, a complete diagramembodying my invention will appear.

By projecting horizontally, any contact may be identified with itsoperating coil by the markings associated, the coil with its associatedcircuits may be located, and other contacts on the same switch or relayoperating simultaneously in other circuits may be located. I

To reduce the diagram to a minimum only the circuits for two cars A andB are illustrated. (Certain exceptions appear where for clearnesscircuits for three cars are shown.) It will be understood that thesystem may be extended to include any number of cars, by obviousduplicating of circuits and cross connections.

Wherever possible apparatus individual to car B is given the samemarkings as' the corresponding apparatus for car A but the marking ispreceded by the letter B. Thus relay 3DY for car A is marked BSDY forCar B. A third cars relay would be marked C3DY.

GENERAL DESCRIPTION The several cars of the bank of elevators are eachdriven by an individual Ward Leonard variable voltage motor drive. Thestarting of each car is controlled by a master switch on the car whichmay also control the closingand opening of power operated doors.Acceleration occurs automatically. Stopping is automatic and each carstops for calls registered on its system. Slowdown occurs atpredetermined positions in advance of the floor such that the stoppingaccurately at the floor occurs with the minimum of shaft travel and inthe minimum of time.

My invention may be used with elevators in which the slowdown isinitiated manually in responseto a signal in each elevator cab. Calls 1for stopping the cars or stop signals may be registered on individualfloor push buttons in each car or on push buttons at each floor commonto all the cars formingthe bank.

The floor calls may be registered on a common call storing relay andcontrol the stopping of all cars equally or they may be registered onrelays 7 individual to each car and be efiective to control The cars arekept in proper order and on proper schedule by a dispatcher that signalscars at terminal floors when to leave. The dispatcher also givespreparatory signals to advise the car operator that his car will receivethe next start signal. 7

To assist in keeping cars on their schedule and prevent as far, aspossible their being unreasonably detained I have provided quota relaysto limit the number of calls a'car can receive and thereby limit thenumber of stops the car will make in a given trip.

Any car standing at a terminal waiting 'to receive a start signal willreceive the signal immediately if its quota becomes filled, that is, ifit has accepted a predetermined number of fioor calls.

A car that does not have its quota filled may pass another car that hasbeen retarded by having a large number of calls to answer. In this eventthe passing car will answer calls registered on the tardy car,'therebyhelping the slow' car ing car does not have its quota, any additionalstops for calls registered on the other car will add to the quota numberof the passing car.

The quota circuit may be arranged to count only hall calls, or both hallcalls and car calls, or hall calls and additional stops such as its owncar calls or hall calls of other cars, or it may count registered hallcalls, car calls and additional stops for other cars hall calls.

Under the condition that a car leaves a terminal in a shorter thannormal interval after the preceding car left, due to its having receivedits quota of calls, the next car to leave will start timing its normalinterval from the time of departure of the early leaving car.

If there is no car at the top terminal at the time the last car leavesany down calls between the terminal and the position of the car last toleave'the terminal will be registered on the up moving car nearest tothe terminal. If this car receives its quota of down calls while stillon up motion subsequent down calls in the zone will be registered on thenext nearest car to the terminal.

Car buttons.

Car button holding coils.

Car call stopping relay. Hall call stoppingrelay.

Hall call storing relay.

Down car selecting relays.

Up car selecting relays.

Down floor lanterns.

Up floor lanterns.

IUL TT Top terminal relay. LT Lower terminal relay. QR Quota relay.

QK QJ ISQ ZSQ 3SQ AND Dispatcher next down relay. ANU Dispatcher next uprelay. ASD Dispatcher start down relay. ASU Dispatcher start up relay.ATE, Dispatcher disconnect relay.

Chain driving relays.

Quota stop counting relays.

TDMDown dispatcher signal storing relay. TUMUp dispatcher signal storingrelay.

Down interval relays.

Up interval relays.

4TU 'I'DH Down impulsing relay. 'I'UH Up impulsing relay.

TDJ }Down dispatcher chain driving ielays.

TUJ }Up dispatcher cham driving relays.

Description of the apparatus Referring now to Fig. 1, car A is shownsuspended by cable I which passes over driving sheave 2 to counterweight3. The sheave 2, a driving motor 5, and a brake sheave Bare mounted on acommon shaft 4. An electromagnetic brake magnet l releases brake shoeswhich are spring applied in a well known manner. A floor selector 9 isalso driven by shaft 4 through a mechanical connection so that aselector carriage 8 driven by a lead screw Ill moves in accordance withmovements of motor 5 and car A.

Selector 9 has a plurality of rows of stationary segments i2 with whichbrushes ll carried by brush carriage 8 make successive contact as willbe explained more fully in connection with Fig. 11.

Car A is provided with two electromagnetic inductors IE and IF. InductorIE termed a slow down inductor is provided with a coil E and twonormally closed contacts El and E2. The latter cooperate with plates ofmagnetic material l4l 5 mounted along the elevator shaftway. When coil Eis energized both contacts remain in the deenergized position. As car Amoves up the shaft contact El is brought near plate It and magneticattraction causes armature l9 to move and thereby open contacts El. Whenthe armature moves to the energized position it remains there until thecoil is deenergized. Similarly, contacts Fl of stopping inductor IF openwhen the latter is brought into cooperative relation with plate l6 asthe car moves up the shaft.

In a similar manner contacts E2 and F2 cooperate with plates l5 and llwhen the car is moving down. Each floor served by car A has a set ofplates. Slow down and stopping of the car are caused by the opening ofthese contacts and the car stops at a given floor by the properselection of the time for energization of the coils of the inductors.This selective energization is accomplished by the brushes and segmentsof the floor selector 9 as will be described later.

The energization of the inductors may be accomplished manually byreleasing the handle of a car starting switch 24 in response to theflashing of a car stopping signal l8. The latter is operated throughselector action as will be described later.

In the event that it is not desired to stop the car by the releasing ofthe car starting switch 24, provision is made for energizing inductorcoils E and F automatically in response to the operation of car pushbuttons 25 and floor push buttons 26. One button for each intermediatefloor served is provided in car buttons 25 (three are illustrated).These serve to stop the car in either direction of travel. They are eachprovided with a coil which when energized will hold the button in theoperated position but will not move the button to the actuated position.When the coil is deenergized a spring moves an acuated button to theunoperated position.

An up button 26b and a down button 26a are provided at each floor commontoall the cars to stop any car of the bank.

Each car has an up and a down signal light 2'l'-28 associated with itsdoor at each floor.

Each car is provided with a dispatcher disconnecting button 29 forincluding or excluding the car from a dispatching system. Thisdispatching system automatically operates signal lamps to advise eachcar operator the most desirable time to start his car. These signals areindicated in Fig. 1, reference character 3| being a Next up signal, 32 aNext down, 33 a Start up and 34 a Start down signal.

A second car B is indicated in Fig. 1 with parts as described for car Awith the exception of the hall car stopping buttons 26 which are commonto all cars. Similar parts will bear similar designating numerals exceptthat to avoid confusion each numeral is preceded by the letter B. Thusthe motor for car B is designated B5.

Figure 2 illustrates a motor driven timing mechanism TM that is usefulfor determining the intervals at which the cars should leave thedispatching floors. A motor armature ll, preferably of the directcurrent type provided with a shunt field Q2, drives a shaft 44 through aspeed reducing gear 43. A plurality of earns 45 are mounted on shaft 44.Each cam as it turns closes a set of contacts 41 and 48 by moving apivoted lever 46. A spring 49 is arranged to open the contacts when thecam rotates further. The various cams are placed on the shaft so thatthe contacts close and open in a sequence which repeats for eachrevolution of the shaft 44.

Referring now to Fig. 11, I have illustrated an arrangement of selectorsegments and contacts that is useful in one embodiment of my invention.Segments for five floors for both up and down car motion are shown. Therelative length and location of the segments is shown with respect tolines representing floor levels on the assumption that when a car isstopped at a floor the moving brushes II will be positioned at the linefor the corresponding floor. Thus in Fig. 11, the parts are positionedcorrectly for the car at the third floor level.

Down segments l3 are shown to the left of the lead screw 9 that movesbrush carriage 8 up and down. Up segments l2 are shown to the right.Brush carriage 8 is arranged to tilt with the motion of the screw l0 sothat on down motion of the car brushes will engage segments l3 and willnot engage segments l2. When the car reverses and moves in the updirection, friction between screw l0 and the threaded portion ofcarriage 8 will tilt the carriage so that brushes will engage segmentsl2 and will disengage segments l3.

Fig. 10 shows an alternate method of operating the quota relay in whichthe quota number is a function of the calls registered on a car and thetotal number of cars that are on the down motion. Motor 2335 drives a.nut 2M carrying a brush 202, moving it over stationary contacts 203.

A second brush 204 is also driven over stationary contacts 295,

Motor armature 206 is connected in a bridge circuit with four resistors2l]62 [11-208-209. Normally the arms of the bridge are balanced so thatno current flows through armature 200. If the resistance of arm 286becomes less by having one or more sections shorted by the closing ofcontacts ZDRS to 4DR6 then current will flow through the armature 208 bythe path Ll2fl62DiJ2U8L2,

shunt field 200a is so connected that rotation will occur to move brush2E2 to short out one or more sections of resistor 2%. This actioncontinues until the bridge is again balanced and no actuating currentflows through armature 200.

The simultaneous movement of brush 204 over segments 285 occurs. If itcomes in contact with a segment connectedto quota setting switch 2 l B,quota relay QR becomes energized.

It will be readily seen that any desired movement of brush 2% can berequired to close the circuit to quota relay QR by moving switch 2M.Thus if the position illustrated of brush 204 to the first connectedsegment is required, this requires the minimum movement of brush 262 andmotor 290 which corresponds to the minimum resistance shorted in arm296.

Two contacts X2 and BX2 are shown shorting sections of resistance ofarms 2%. With contacts X2 open, the shorting of one of the sections bycontacts ZDRE to lDRB will result in a balanced bridge so that anadditional section must be shorted to cause the minimum movement ofbrush 2%. Thus car A on a down trip opens contacts X2 and increases thenumber of calls required to operate relay QR by one. If both cars A andB should be on the down trip simultaneously contacts X2 and BX2 wouldboth be open and three sections would have to be shorted to get theminimum movement. Thus the quota number is increased in pro-portion tothe cars on a down trip,

In Fig. 11, notations have been made associated with each row ofsegments indicating the function of the segments in the control system.These notations will be better understood in connection with thedescription of the diagram and the operation of the system that follows.

The apparatus described in the preceding paragraphs, together with therelays of Figs. 3A through 9A and the circuits of Figs. 3 through 9,show one embodiment of my invention. The sequence of operation of thecircuits can best be understood in connection with a description of thecircuits and the operation.

Description of the circuits When switch LS in Fig. 3 is closed, supplywires LI and L2 become energized from a D. C. supply circuit L-|- and L(not shown). The armature MA of elevator motor 5 is shown connected in aloop circuit with generator armature GA and generator series field GS inthe well-known Ward-Leonard connection for driving motors. Generatorarmature GA is separately driven at a constant speed and suppliesvoltage to motor armature MA in accordance with the excitation of shuntfield GF. The shunt field MF of motor 5 is connected directly across thesupply lines and receives continuous excitation,

Generator field GF may be energizedin either directionfor driving theelevator either up or down. It may be energized at a low value forlanding speed or at a high value by closing contacts VI for high speed.Intermediate steps may be used if so desired. The circuit for energizingthe generator field at landing speed for up car motion may be tracedthrough the following elements.

The sequence of operation for starting and stopping the car is asfollows (assuming switch 82 thrown to the position opposite that of thefigure). When start lever 2d is thrown to the left, coil U is energizedthrough a circuit includ ing the elevator door contacts 63, assuming thedoors closed and therefore the door contacts closed.

L l -2 l-F l U-B 3-L2 (Fig. 3)

The brake coil 7 becomes energized.

Ll-l-U2L2 (Fig. 3)

Coil V becomes energized causing the car to run at full speed byshorting resistor 6|.

LlU lEIVL2 (Fig. 3)

The car is stopped by centering the lever of car starting switch 24.

Coil U remains energized.

LlU5Fl-U-63L2 (Fig. 3)

The coil of relay G and inductor coil E becomes energized.

Inductor plate [4 (Fig. 1) for the next floor coil E is energized byeither contact CC! or contact HCI closing.

LICCI or HCl-coils E and GU6L2 When holding relay G becomes energized,it establishes a self-holding circuit interrupted by contact U6 when thecar stops.

Car calls are registered on car push buttons 25 (Fig. 1). If button 3Cis operated, it is held in the operated position by coil 3CI-I andselector segments H6 and H59 are connected to conductor Li. If the caris on down motion, brush li'll will be in position to contact segment H6as thecar approaches the third floor. Relay CC becomes energized toinitiate slowdown, as described previously.

If switch 62 had been thrown to the other direction signal lamp [8 inthe car would be energized instead of coil of relay CC. This lamp warnsthe operator when he should center start lever 24 to stop in response tothe call for this floor.

If the car had been on up motion, brush H2 would be moved to a positionto engage segment i239 as the car approached the third floor in the

